Dean makes himself unpopular with Lorelai and Rory when he says it seems nice that Donna Reed likes cooking for her family and that she seems happy to do so. Even the most ardent Dean fan must feel at this point that he and Rory are not perfectly suited to each other. He receives short shrift from the two Gilmores, and in the end is stifled into silence, with a “Hey, I’m not saying anything”.
Apart from showing a serious discrepancy in the values of Rory and Dean, it also demonstrates how Lorelai and Rory don’t allow the men in their lives to have any say in things. When Dean first came to a movie night at their house, he was basically told he wasn’t allowed to choose the movie, and had to run any suggestion past Lorelai (as he picked an inappropriate movie, it didn’t seem unjustified at the time).
But now he isn’t even allowed to voice an opinion on what the Gilmores are watching. It raises the question of what role Dean has in Rory’s life: is he just there to bring pizza, look handsome, kiss her, tell her she’s pretty, phone her fifty times a day, and agree with everything she says? Even Donna Stone got to do a lot more than that!